Bottom for metallurgical furnaces



June 7, 1949.

lT. M. FAIRCHILD BOTTOM FOR METALLURGICAL FURNACES Filed Aug. 5, 1944 Patented June 7, 1949 BOTTOM FOR METALLURGICAL FURNACES Theodore M. Fairchild, Johnstown, Pa., assignor Company, a corporation of to Bethlehem Steel i 'Pennsylvania Application August 5, 1944, Serial No. 548,305

' 1 Claim.

This invention relates to improvements in bottoms for metallurgical furnaces, and in particular to bottoms for furnaces utilized to heat billets or ingots prior to the forming of said billets or ingots into finished or semi-finished products by rolling or forging.

The several types of bottoms for furnaces of this type, which will be hereinafter referred to as heating furnaces, have heretofore been open to a number of objections.

Oney well known type of bottom that has been used is made yof a plastic' chrome refractory ramming material, This has given good results so far as wearing quality is concerned. However, this type of bottom requires several days to a week to install as it must be rammed in and sintered before it is ready for use. When maximum production is a primary consideration, this prolonged interruption of the operation of a furnace is most undesirable.'

Bottoms have also been built of standard shape refractory bricks of either chrome or magnesite. While this type of bottom is cheaper than the plastic rammed bottom and can be installed'in a very short time, both the chrome bottom and I have found in several installations that very satisfactory results are obtained with a bottom in which one row of magnesite brick alternates with two rows of chrome brick all the way across the bottom of the furnace as shown in the drawthe magnesite bottom have certain objectionable characteristics. Thus,` the chrome bottom tends to absorb thel slag, cinder, etc. formed in the furnace from the scale on the billets or ingots and from other molten material from the walls or roof of the furnace. This results in a rapid fluxing away of the chrome brick, so that this type of bottom has a relatively short life.

Magnesite brick, on the other hand, while having a relatively long life, is objectionable in that the aforementioned slag etc. will accumulate and build up on the surface of the brick. This makes it diiiicult to push the billets through the furnace, and requires frequent interruptions of the furnace operation to. remove the accumulated material from the furnace bottom.

I have discovered that if a bottom is formed of a combination of magnesite bricks and chrome ings. Furthermore a furnace bottom formed of alternate areas of hardened plastic refractory material of the kind used for the aforesaid brick elements is a structure made in accordance with my invention; it may be intercalated in rows, or

areas of various contours, laid in situ or precast, without departingv from the spirit of my invention.

In actual operation with a furnace bottom as described in the two preceding paragraphs, I find that a considerable proportion of the slag and cinder is absorbed by the chrome bricks, which are partially iiuxed away thereby. The magnesite bricks, however, not being attacked by the slag, remain as skids along which the billets maybe moved. Thev amount of slag which accumulates on the individual rows of magnesite brick has been found not to be objectionable, and does not materially affect the operation of the furnace;

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

A bottom for a heating furnace having a surface comprising rows of chrome bricks alternating with rows of magnesite bricks.

THEODORE M. FAIRCHILD.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 367,251 swincieli July 26, 1887 OTHER REFERENCES Industrial Furnaces, Vol. I, by W. Trinks, third edition, pages 261 and 262.

Modern Furnace Technology, page 425 by H. Etherington. 

